v2.0.0 - Change API

• Change API #20 - @jagaapple
  • In v1, image paths are exported by path property like import { path } from "./xxx.png";
  • From v2, image paths are exported by default like import path from "./xxx.png";
  • In v1, React image elements are exported by default like import Image from "./xxx.png";
  • From v2, React image elements are exported by element property like import { element as Image } from "./xxx.png";
• Add support for Babel 7 #21 #23 - @jagaapple
• Update dependencies #18 - @jagaapple
• Update development environment #22 #25 - @jagaapple
  • Add CircleCI settings
  • Use webpack-dev-server instead of webpack-serve
  • Use ESLint instead of TSLint
• Modify a readme - @jagaapple